Use Unique Colors

• Bright colors tend to get the most attention.Polka Dot Images/Polka Dot/Getty Images
  
  Choose colors that accentuate the message you would like to get across with your art form. Politically-based graffiti can use red, white and blue as a theme. If the message is based around upset or pride in foreign affairs, use the colors that represent the colors of the country you are referencing. Pastels are often used for messages of hope revolving around children. Dark greens, browns and grays are often used for military references. Historically, bright primary colors garner the most attention from passers-by.
  
  

Fading and Shading

• Tinting the blue wave with white makes the image pop.Jupiterimages/Comstock/Getty Images
  
  Fading and shading with spray paint requires a technical skill that many beginners have yet to master. To make your art stand out among the rest, try using a color gradient, where you start a letter or image in one color, fade it out using less and less paint, and then fade-in a separate color until that new color takes over completely. Shadowing gives graffiti a three-dimensional look that will pop out at the people walking by.
  
  

Font Matters

• The font you use can further entrench your message.Stockbyte/Stockbyte/Getty Images
  
  Choose a font that furthers your message. Spiky lettering indicates distress or discontentment, whereas rounded letters show a smooth calm. Cartoonish calligraphy is often used in satirical messages but can also be seen in art that is purely meant for fun. Whatever font you choose, make sure it is easy enough to read. Too much complication, and your prospective audience will glaze over your piece.
  
  

Don't Ignore the Background

• Completely fill the background, giving viewers the full scope of your message.Jupiterimages/Photos.com/Getty Images
  
  Graffiti has potential for being more than just words or images on a canvas. Use the blank space to your full advantage by filling it completely. Abstract designs that enhance the feel of your piece will keep a viewer standing there longer, in turn increasing your message's power. Use symbols, landscape images or simple color shapes to draw attention to your main words or images while creating a smooth background that's either easy or hard to look at, depending on your motive.